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Perovskite oxides are regarded as promising electrocatalysts for water splitting due to their cost‐effectiveness, high efficiency and durability in the oxygen evolution reaction (OER). Despite these advantages, a fundamental understanding of how critical structural parameters of perovskite electrocatalysts influence their activity and stability is lacking. Here, we investigate the impact of structural defects on OER performance for representative LaNiO3 perovskite electrocatalysts. Hydrogen reduction of 700 °C calcined LaNiO3 induces a high density of surface oxygen vacancies, and confers significantly enhanced OER activity and stability compared to unreduced LaNiO3; the former exhibit a low onset overpotential of 380 mV at 10 mA cm−2 and a small Tafel slope of 70.8 mV dec−1. Oxygen vacancy formation is accompanied by mixed Ni2+/Ni3+ valence states, which quantum‐chemical DFT calculations reveal modify the perovskite electronic structure. Further, it reveals that the formation of oxygen vacancies is thermodynamically more favourable on the surface than in the bulk; it increases the electronic conductivity of reduced LaNiO3 in accordance with the enhanced OER activity that is observed. [ABSTRACT FROM AUTHOR]

Oxide perovskites have emerged as an important class of materials with important applications in many technological areas, particularly thermocatalysis, electrocatalysis, photocatalysis, and energy storage. However, their implementation faces numerous challenges that are familiar to the chemist and materials scientist. The present work surveys the state-of-the-art by integrating these two viewpoints, focusing on the critical role that defect engineering plays in the design, fabrication, modification, and application of these materials. An extensive review of experimental and simulation studies of the synthesis and performance of oxide perovskites and devices containing these materials is coupled with exposition of the fundamental and applied aspects of defect equilibria. The aim of this approach is to elucidate how these issues can be integrated in order to shed light on the interpretation of the data and what trajectories are suggested by them. This critical examination has revealed a number of areas in which the review can provide a greater understanding. These include considerations of (1) the nature and formation of solid solutions, (2) site filling and stoichiometry, (3) the rationale for the design of defective oxide perovskites, and (4) the complex mechanisms of charge compensation and charge transfer. The review concludes with some proposed strategies to address the challenges in the future development of oxide perovskites and their applications. [ABSTRACT FROM AUTHOR]

A series of supported Ni nanoparticles on a flower-like porous LaNi 0.6 Al 0.4 O 3 (LNAO) perovskite carrier ( z Ni/LNAO; z  = 5, 10 and 15 wt%) were successfully synthesized using a controlled self-assembly sol-gel method. The experimental results showed that the presence of Ni nanoparticles markedly enhanced the reaction rate of CO conversion, namely from 12.4 mmol/(g cat h) over LNAO to 244 mmol/(g cat h) over 10 wt% Ni/LNAO. The porous LNAO perovskite support provides both a large surface area to well disperse Ni nanoparticles and active sites for the methanation reaction, thus resulting in a catalyst with activity (per gram of catalyst basis) at least comparable to other nickel metal-based supported catalysts reported so far and with very good stability. Reaction rates calculated based on Ni exposed surface and total Ni amount revealed that Ni active sites in the Ni nanoparticles and bulk perovskite were distinct. [ABSTRACT FROM AUTHOR]

Abstract: The rational design of low‐cost transition metal catalysts that exhibit high activity and selectivity may be the most significantly investigated in heterogeneous catalysis. In this study, Co3‐xMnxO4 (x=0.75, 1.0, and 1.5) mixed metal oxides were successfully synthesized by a controlled template‐free autoclave strategy and studied for toluene oxidation. It is found that the Co‐rich sample showed markedly enhanced activity and the 3D dandelion‐like Co2.25Mn0.75O4 catalyst exhibited in the highest toluene oxidation rate (8.9 μmol/(gcats)) and a 100 % toluene conversion at 239 °C. In situ DRIFTS study indicates that toluene was sequentially oxidized to benzyl radical, benzaldehyde, benzene, oxalic acid, and finally to CO2 and H2O. The interaction between Co and Mn, in conjunction with the high concentration of surface oxygen species and rich surface oxygen vacancies, reasonably explains the elevated catalytic activity and thermal stability for toluene oxidation over 3D flower‐like Co3‐xMnxO4 spinel catalysts. [ABSTRACT FROM AUTHOR]

This feature article summarizes the recent progress in porous perovskite oxides as advanced catalysts for both energy conversion applications and various heterogeneous reactions. Recently, research has been focused on specifically designing porous perovskite materials so that large surface areas can be harnessed and surface properties can be improved. Numerous potential applications of porous perovskites have been investigated, including heterogeneous catalysis and air battery applications that rely on interactions and/or reactions of other components with porous perovskites. The main objective of this article is to examine the progress of recent research studies on porous perovskite nanomaterials, including the preparation methods and their applications in catalysis and batteries. The wide variety of the related knowledge on porous mixed oxides can provide guidance for researchers with interests ranging from the design of functionalized materials to the field of heterogeneous catalysis and electrochemical applications. [ABSTRACT FROM AUTHOR]

Lanthanide-doped upconversion nanoparticles (UCNPs) have unique photoluminescent properties that are useful in many biomedical applications. Modification of UCNPs with a polymer layer can confer additional functionality such as biocompatibility, stability in vivo, or drug delivery capability. It is also important that the modification process can be controlled precisely and without having adverse effects on the UCNPs luminescence properties. Herein, a polymer shell was grafted directly from the surface of UCNPs (grafting from) via visible light (λmax = 635 nm, 0.7 mW/cm2) regulated photoenergy/electron transfer-reversible addition fragmentation chain transfer polymerization (PET-RAFT). The polymerization kinetics, grafting density, and thickness of the surface-tethered polymer chains can be tuned precisely by adjusting the monomer and RAFT agent ratio or the light exposure time. This approach also permits temporal control of the polymerization process. That is, the polymerization process can be initiated, halted, or terminated by switching the light source on and off. By limiting the non-radiative decay caused by surface defects, as well as from vibrational deactivation from solvents, the polymer shell enhanced the upconversion luminescence of the silica-coated UCNPs. This investigation paves the way for the development of UCNPs with controlled properties for various application requirements. [ABSTRACT FROM AUTHOR]

This invited review highlights recent progress in the various classes of heterogeneous catalysts for methane combustion. These combustion catalysts provide a high-efficiency, clean energy source for natural gas vehicles and power plants. This review examines bimetallic systems, and a variety of oxides including single metal oxides, perovskites, spinels, and hexaaluminates. Noble metal mixed oxides exhibit superior catalytic activity due material-specific supports, additives, preparation methods, poisoning, regeneration and surface structure. Kinetic aspects, mechanisms, and the latest studies concerning density functional theory modelling are discussed in conjunction with particle oxidation/reduction mechanisms. The extensive background knowledge on the methane combustion reaction provided by this review provides guidance for researchers with interests ranging from the field of heterogeneous catalysis to the engineering of new high performance materials in environmental and chemical engineering. Graphical Abstract: [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Highlights: [•] LSCO synthesized via a novel and facile one-pot dextrose-assisted hydrothermal route. [•] High-surface-area nanowire LSCO is prepared by the DHR method. [•] Surface area, Oads content, and reducibility account for the good catalytic activity. [•] Catalytic activity is related to surface area, oxygen adspecies and reducibility. [•] l-Lysine/dextrose ratio can greatly influence on the morphology and pore structure. [ABSTRACT FROM AUTHOR]

Highlights: [•] High-surface-area 3DOM La0.6Sr0.4MnO3 is prepared by the PMMA-templating method. [•] Surfactant addition is critical in 3DOM structure formation with nanovoid-like walls. [•] The calcination procedure is a key step in the formation of 3DOM structure. [•] 3DOM La0.6Sr0.4MnO3-DP3 performs best in the combustion of methane. [•] Surface area, Oads, and reducibility determine the activity of 3DOM La0.6Sr0.4MnO3. [Copyright &y& Elsevier]

Highlights: [•] Mesoporous Co3O4 and nano-Co3O4 were prepared by the hard template method and precipitation method. [•] 3D-Co3O4 has the clear special pore structure, large surface area and surface active species. [•] 3D-Co3O4 shows the best catalytic activity due to abundant surface oxygen species and active Co3+ species. [•] 3D-Co3O4 has excellent reaction stability after continuously reacting for 160h. [ABSTRACT FROM AUTHOR]

A series of novel metal-oxide-supported CeO2 catalysts were prepared via the wet impregnation method, and their NH3-SCR activities were investigated. The Ce/TiO2-SiO2 catalyst with a Ti/Si mass ratio of 3/1 exhibited superior NH3-SCR activity and high N2 selectivity in the temperature range of 250-450 °C. The characterization results revealed that the activity enhancement was correlated with the properties of the support material. Cerium was highly dispersed on the TiO2-SiO2 binary metal oxide support, and the interaction of Ti and Si resulted in greater conversion of Ce4+ to Ce3+ on the surface of the catalyst compared to that on the single metal oxide supports. As a result of in the increased number of acid sites on Ce/TiO2-SiO2 that resulted from the addition of SiO2, the NH3 adsorption capacity was significantly improved. All of these factors played significant roles in the high SCR activity. More importantly, Ce/TiO2-SiO2 exhibited strong resistance to SO2 and H2O poisoning. After the addition of SiO2, the number of Lewis-acid sites was not decreased, but the number of Brønsted-acid sites on the TiO2-SiO2 carrier was increased. The introduction of SiO2 further weakened the alkalinity over the surface of the Ce/TiO2-SiO2 catalyst, which resulted in sulfate not easily accumulating on the surface of the Ce/TiO2-SiO2 catalyst in comparison with Ce/TiO2. [ABSTRACT FROM AUTHOR]

Ordered mesoporous silicas are widely used in separation science and catalysis, however, their slow batch synthesis is a barrier to scale-up and new applications. SBA-15 is one of the most extensively studied and commercially available mesoporous silicas, whose textural properties can be readily tuned through judicious choice of synthesis conditions. Here we demonstrate the continuous flow synthesis of SBA-15 in high yield at 80 °C using a simple tube reactor without any mixing device. The resulting SBA-15 exhibits excellent textural properties, with a BET surface area of 566 m2 g−1 and ordered 5.1 nm mesopore channels in a p6mm arrangement, akin to those from conventional batch synthesis, but with far higher productivity than previously reported in batch or flow (5.3 g L−1 h−1 versus 0.4 and 0.6 g L−1 h−1 respectively). • A continuous flow protocol for the synthesis of mesoporous SBA-15. • Simple flow reactor configuration. • High SBA-15 yields (∼80%) at short residence time (17 min). • Increased productivity of flow synthesis demonstrated. • Control over physicochemical properties via tuning of synthesis parameters. [ABSTRACT FROM AUTHOR]

Keywords: electrocatalysts; oxygen evolution reaction; perovskite; surface defects EN electrocatalysts oxygen evolution reaction perovskite surface defects 14355 14355 1 10/21/21 20211019 NES 211019 B The impact of defect generation b by thermal reduction on the structure and electrocatalytic performance of LaNiO SB 3 sb has been examined in a combined experimental and theoretical approach. Electrocatalysts, oxygen evolution reaction, perovskite, surface defects. [Extracted from the article]

Highly dispersed Ag nanoparticles supported on high-surface-area 3DOM La0.6Sr0.4MnO3 were successfully generated via the dimethoxytetraethylene glycol-assisted gas bubbling reduction route. The macroporous materials showed super catalytic performance for methane combustion. [ABSTRACT FROM AUTHOR]

A bimetallic RhNi/Al 2 O 3 catalyst prepared by galvanic replacement (GR) offers enhanced catalytic CO 2 hydrogenation to selectively produce methane. • Galvanic replacement offers a facile route to bimetallic Rh@Ni core–shell catalysts. • Bimetallic Ni@Rh core–shell catalysts offer significant rate enhancements for CO 2 methanation. • Operando IR identifies reactively-formed CO as the key intermediate to CH 4 production. • Surface formate is a catalytic spectator in methanation. CO 2 utilisation as a chemical feedstock could transform fuels production and help mitigate climate change. Direct CO 2 reduction for energy production requires the development of active, stable, and low-cost catalysts selective for methane. A bimetallic Ni@Rh core–shell catalyst prepared by galvanic replacement (GR) exhibits a 3.5-fold rate enhancement for CO 2 methanation relative to an analogue prepared by chemical reduction (CR) and is twice as active as monometallic Rh/Al 2 O 3. Superior performance of RhNi/Al 2 O 3 (GR) is attributed to Rh dispersion as an atomically thin RhO x shell encapsulating Ni nanoparticles, stabilised by a strong Rh-Ni interaction. Operando IR spectroscopy identifies reactively-formed CO from the dissociative chemisorption of CO 2 over Rh as the key intermediate for methane production. Surface formate from the dissociative chemisorption of CO 2 and subsequent hydrogenation (via spillover from Rh sites) over alumina is a catalytic spectator. This mechanistic insight paves the way to high activity nanostructured catalysts for CO 2 methanation. [ABSTRACT FROM AUTHOR]

Water electrolysis is a promising method for efficiently producing hydrogen and oxygen, crucial for renewable energy conversion and fuel cell technologies. The hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) are two key electrocatalytic reactions occurring during water splitting, necessitating the development of active, stable, and low-cost electrocatalysts. Transition metal (TM)-based electrocatalysts, spanning noble metals and TM oxides, phosphides, nitrides, carbides, borides, chalcogenides, and dichalcogenides, have garnered significant attention due to their outstanding characteristics, including high electronic conductivity, tunable valence electron configuration, high stability, and cost-effectiveness. This timely review discusses developments in TM-based electrocatalysts for the HER and OER in alkaline media in the last 10 years, revealing that the exposure of more accessible surface-active sites, specific electronic effects, and string effects are essential for the development of efficient electrocatalysts towards electrochemical water splitting application. This comprehensive review serves as a guide for designing and constructing state-of-the-art, high-performance bifunctional electrocatalysts based on TMs, particularly for applications in water splitting. [ABSTRACT FROM AUTHOR]

The surface atomic arrangement and defective structures of electrocatalysts play a crucial role in determining their catalytic activity and selectivity. Hematite (α-Fe2O3) nanostructures with oxygen vacancies are promising electrocatalysts for the oxygen reduction reaction (ORR) due to their low-cost and environmental friendliness. However, a systematic study of their ORR performance, especially selectivity at high oxygen vacancy concentrations, is still lacking. In this study, we synthesized α-Fe2O3 nanosheets with surface oxygen vacancies using a simple solvothermal reaction followed by a liquid phase NaBH4 reduction method. The oxygen vacancy amount was adjusted by varying the concentrations of NaBH4 solution, and it was found that increasing the oxygen vacancy concentration from 11.4% to 43.4% improved the ORR activity, but further increasing it to 77.3% deteriorated the crystalline quality and thus affected the ORR performance. The optimized sample (α-Fe2O3-1 M), treated with a 1 M NaBH4 solution, showed a high limiting current density of 5.75 mA cm−2 at 0.4 V vs. the reversible hydrogen electrode (RHE). The observed enhancement in ORR activity can be attributed to the optimal surface oxygen vacancies, which improve catalytic kinetics and increase the exposure of active sites. [ABSTRACT FROM AUTHOR]

Regulating S doping sites in mesoporous carbon spheres is achieved by annealing with selected precursors. The experimental and theoretical results demonstrate that S doping between the carbon layers enlarges interlayer spacing and facilitates potassium ion adsorption, which is favorable for fast potassium ion storage. [Display omitted] • Sulfur-doped mesoporous carbon spheres with abundant internal surfaces are synthesized. • The sulfur doping sites are controlled by the sulfurization of different precursors. • The optimized sample shows excellent rate capability for potassium storage. • The good electrochemical performance is ascribed to the controlled sulfur doping sites. Mesoporous carbon spheres (MCSs) show great potential for using as high-performance anodes in potassium-ion batteries (PIBs). Design and synthesis of MCSs with suitable multiscale structures and heteroatom doping or co-doping in MCSs are successfully employed to optimize the ion and electron transportation, however, it is still a challenge to explore MCS-based anodes with satisfactory potassium storage performance. In this work, we report novel S-doped MCS samples with abundant internal surfaces for potassium storage. The S doping sites are controlled during the synthesis, and the effect of different doping sites on the potassium storage is systematically studied. It is found that S doping between the carbon layers enlarges interlayer spacing and facilitates potassium ion adsorption. Consequently, the optimized sample shows an excellent rate capability of 144 mAh/g at 5.0 A/g, and a high reversible specific capacity of 325 mAh/g after 100 cycles at 0.1 A/g with a capacity retention of 91.2%. The important role of element doping sites on ion adsorption and ion storage performance is confirmed by theoretical investigations. Controlling the doping sites in MCSs provides a new approach to designing high-performance electrodes for energy storage and conversion applications. [ABSTRACT FROM AUTHOR]

Solar-based radiant heating systems represent a sustainable, and relatively low-cost, technology to raise the temperature of the interior thermal mass of our buildings. Through the use of direct absorption solar thermal collectors, the same working fluid which absorbs the solar energy can be used to transfer the energy for storage in the thermal mass of the structure using a network of pipes embedded in concrete floors. This study investigates a promising working fluid which can be used in such systems – one which is based on multi-walled carbon-nanotubes suspended in normal base fluids. A major stumbling block affecting the wide spread use of carbon-nanotube nanofluids is their low dispersion stability at elevated temperatures, which significantly reduces the absorption capabilities of the nanofluids and could lead to clogging of the pumps used to circulate the fluids. In this paper, we report on a scalable UV-ozone (UVO) treatment technique to produce highly stable dispersions for the elevated temperatures experienced by working fluids in radiant heating systems. To probe suitability of UVO treated multi-walled carbon-nanotube (MWCNTs) for solar-assisted radiant heating systems, this paper investigates the effects of exposure time and temperature on stability, optical absorbance properties, the extent of functionalisation, and the photothermal conversion performance of UVO-treated MWCNT nanofluids. No agglomeration or degradation of the MWCNTs was observed at elevated temperatures (up to 150   °C), highlighting the stability of proposed nanofluids. [ABSTRACT FROM AUTHOR]

A Ni loaded catalyst on mesoporous ceria, with a large surface area, prepared through the surfactant-assisted precipitation and impregnation method was investigated as an efficient catalyst for propane partial oxidation to produce synthesis gas. The results show that 2.5 wt% Ni/CeO2 had the optimum Ni loading, exhibiting the highest catalytic propane conversion. It also showed excellent stability, with no obvious activity drop after a 10 h time-on-stream reaction and slightly decreased in H2 and CO yields. The investigation of the reactant composition effect on carbon formation showed that by decreasing the C/O2 ratio the content of accumulated carbon decreased and propane conversion increased. The good activity of the Ni/CeO2 can be ascribed to the high surface area and rich surface defects of the ceria support and a high dispersion of active sites (Ni nanoparticles). [ABSTRACT FROM AUTHOR]

Using [Ni{(POEt)3}4] as catalyst precursor for the catalytic isomerization of allylbenzene to beta‐methylstyrene, time‐course studies suggest a mechanism that is consistent with an autocatalytic reaction. The sigmoidal curve observed when plotting conversion vs. time fits exceptionally well to a kinetic model of an autocatalytic process (R2 = 0.998). We show that the uncoordinated phosphite, generated during the catalyst activation, reduces the acid concentration and, consequently, has a detrimental effect on the formation of the protonated active nickel catalyst. The nickel complex protonation is seen as a key step in forming the active catalytic species. The novel use of a mercury salt as a phosphite scavenger leads to inhibition of the free phosphite's capability to lower acid concentration, improving the catalytic performance of the system, consistent with the mechanism proposed. [ABSTRACT FROM AUTHOR]

The water-gas shift (WGS) reaction has received renewed interest because it is one of the key reactions for producing hydrogen and renewable energy in contemporary technologies like fuel cells and bio-refineries. Catalysts play an important role in WGS reaction for achieving high CO conversion and hydrogen generation activity. Thus, the performance and stability of catalysts are vital for the WGS reaction. In the present work, the CuCe metal-organic framework (MOF) is used as a template to derive the nanostructured Cu/CeO 2 catalyst. The influence of CuCe-MOF templated approach on the WGS activity of Cu/CeO 2 has been established. Different Cu doping levels had a significant impact on WGS activity. Amongst, the Ce 0.8 Cu 0.2 O 2 (Cu2Ce) catalyst had a highest CO conversion (96%). The long-term stability tests further prove that the Cu2Ce catalyst had maintained high CO conversion over 100 h reaction time. XRD and TEM results suggest that different loadings of Cu content have a distinct impact on the dispersion of Cu and the catalytic properties. N 2 O chemisorption results suggest that 20 wt.% of Cu loading resulted in high Cu dispersion (52%) compared to other loadings. The H 2 -temperature programmed reduction (TPR) revealed that the superior catalytic activity of Cu2Ce catalyst could be attributed to the strong reducibility (i.e. lower redox temperature) derived from CuCe-MOF template. It further suggests well-dispersed copper oxide species at low Cu loadings and crystalline copper oxide species at high Cu loadings. This work emphasizes the significance of Cu/CeO 2 catalysts with exceptional catalytic activity and stability for the WGS process with MOF-precursor. [Display omitted] • Cu/CeO 2 catalysts are synthesized using CuCe-BTC-MOF as a porous template. • High Cu dispersion and strong redox behaviour of Cu/CeO 2 are inherited from MOF. • Enhanced CO conversion and a high stability are achieved. • Well-organized MOF-template approach is crucial for improved WGS activity. [ABSTRACT FROM AUTHOR]

Mesoporous nanocrystalline Mg 1-x Ni x Al 2 O 4 (x = 0.10, 0.13, 0.17 and 0.20) with large surface area were synthesized via a simple one-step sol-gel method using nonprecious metals. The prepared Mg 1-x Ni x Al 2 O 4 catalysts exhibit good catalytic performance towards methane and carbon dioxide dry reforming reaction. The catalysts were evaluated by various techniques, including XRD, BET, TPR, TPO, EPR, Chemisorption, SEM and TEM. All the Ni incorporated MgAl 2 O 4 samples possessed high BET area (296–305 m 2 g −1 ) and pore volume (0.47–0.56 cm 3 g −1 ) with small pore size (6.4–7.4 nm) in meso region after calcination at 700 °C. The TPR results suggested strong interaction effect in Ni Mg and the reducibility property of the catalysts improved with the increase of nickel doping. Mg 0.8 Ni 0.2 Al 2 O 4 exhibited the highest activity for biogas dry reforming with 72.6% CH 4 and 80.7% CO 2 conversion at 700 °C. Electron paramagnetic resonance (EPR) results indicated that the incorporation of Ni in MgAl 2 O 4 spinel lattice led to the lattice distortion and formed oxygen vacancies which are a benefit for the dry reforming reaction. [ABSTRACT FROM AUTHOR]

Gamma alumina is one of the widely used supports in catalyst preparation, possessing a high specific surface area and good thermal stability. Spray drying is an efficient way to produce narrow particle size distribution and spherical shape powders. In this study, spray drying method has been implemented to prepare microspherical nanoporous gamma alumina with a high specific surface area. The nanoporous gamma alumina support was utilized in the preparation of various heterogeneous base catalysts. The highest biodiesel yield of 99% was obtained at 6 wt% loading of K/γ-Al2O3 catalyst, using waste cooking oil as feedstock. The obtained results revealed the great potential of the synthesized nanoporous gamma alumina as an effective support for heterogeneous base catalysts preparation in the transesterification reaction. [ABSTRACT FROM AUTHOR]

A simple, template-free and scalable modified sol-gel route was developed for the synthesis of mesoporous flake-like magnesium aluminate spinel (MgAl 2 O 4 ) at low temperature (700 °C) with high surface area (281 m 2 g −1 ). The obtained spinel materials were characterized by means of physicochemical techniques including X-ray diffraction, thermogravimetric analysis, scanning electron microscopy with energy-dispersive X-ray spectroscopy, transmission electron microscopy, Fourier transform infrared spectroscopy and N 2 adsorption-desorption analysis. The propylene oxide was used as gelation and pore forming agent in the sol-gel process. Different morphologies and sizes of flake were generated by the varied synthesis conditions. The result materials reveal that the textural properties of the MgAl 2 O 4 product are strongly associated with the nature and amount of addictive solvent and calcination temperatures. It shows that the BET surface area decrease as the increase of calcination temperature and the optimal temperature of 700 °C result in the pure phase of MgAl 2 O 4 spinel. This synthesis strategy offers a feasible approach for scalable fabrication of mixed metal oxides for various catalytic reactions or catalyst supports due to the large surface area. [ABSTRACT FROM AUTHOR]

Uniform Fe 3 O 4 microflowers assembled with porous nanoplates were successfully synthesized by a solvothermal method and subsequent annealing process. The structural and compositional analysis of the Fe 3 O 4 microflowers were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). The Bruauer–Emmett–Teller (BET) specific surface area was calculated by the nitrogen isotherm curve and pore size distribution of Fe 3 O 4 microflowers was determined by the Barret–Joyner–Halenda (BJH) method. When evaluated as anode material for lithium-ion batteries, the as-prepared Fe 3 O 4 microflowers electrodes delivered superior capacity, better cycling stability and rate capability than that of Fe 3 O 4 microspheres electrodes. The improved electrochemical performance was attributed to the microscale flowerlike architecture and the porous sheet structural nature. [ABSTRACT FROM AUTHOR]

Highly dispersed Ni nanoparticles supported on high-surface-area mesoporous nanocrystalline MgAl2O4 powder was generated by a facile and simple propylene oxide assisted gelation agent route. The mesoporous spinel materials exhibited enhanced catalytic performance for hydrogen production in biogas dry reforming. The obtained spinel catalysts with different Ni loadings after calcination at 700 °C possessed high BET surface areas (236-224 m2 g−1). A narrow pore size distribution in the mesopore range was observed in the samples, and all the samples except 2.5 wt % Ni showed a mesoporous-macroporous structure. The 5 wt % Ni/MgAl2O4 sample showed the highest activity for the biogas dry reforming reaction because of the high dispersion of Ni on the mesoporous surface of the spinel support. X-ray photoelectron spectroscopy revealed that the catalysts with a low Ni loading undergo the exchange of Mg2+ by Ni2+, whereas catalysts with a higher Ni loading undergo the substitution of Al3+ by Ni3+. Thus, appropriate partial Ni substitution in the MgAl2O4 support may play a role in the elevated catalytic performance. [ABSTRACT FROM AUTHOR]

[Display omitted] Graphite is a widely used anode material in commercial lithium-ion batteries (LIBs), but its low theoretical specific capacity and extremely low redox potential limit its application in high-performance lithium-ion batteries. However, developing lithium-ion battery anode with high specific capacity and suitable working potential is still challenging. At present, conductive polymers with excellent properties and graphite-like structures are widely used in the field of electrochemistry, but their Li+ storage mechanism and kinetics are still unclear and need to be further investigated. Therefore, we synthesized the conducting polymer Fe 3 (2, 3, 6, 7, 10, 11-hexahydroxytriphenylene) 2 (Fe-CAT) by the liquid phase method, in which the d-π conjugated structure and pores facilitate electron transfer and electrolyte infiltration, improving the comprehensive electrochemical performance. The Fe-CAT electrode displays a high capacity of 950 mA h g−1 at 200 mA g−1. At the current density of 5.0 A g−1, the electrode shows a reversible capacity of 322 mA h g−1 after 1000 cycles. The average lithiation voltage plateau is ∼ 0.79 V. The combination of ex-situ characterization techniques and electrochemical kinetic analysis reveals the source of the excellent electrochemical performance of Fe-CAT. During the charging/discharging process, the aromatic ring in the organic ligand is involved in the redox reaction. Such results will provide new insights for the design of next-generation high-performance electrode materials for LIBs. [ABSTRACT FROM AUTHOR]

This study aims to investigate the catalytic activity of spinel-type oxides (NixCoyO4) for the oxidation of toluene and carbon monoxide at low temperatures. A series of Ni/Co catalysts with different mole ratios were synthesized via citric acid assisted sol-gel method and the influence of the nickel to cobalt ratios on the properties and catalytic performance of NixCoyO4 were investigated by characterization such as XRD, SEM-EDX, BET, H2–TPR. The results indicate that the catalyst with the Ni/Co atomic ratio of 1.5/1.5 exhibits the highest complete toluene oxidation activity, with 85% toluene conversion rate at 100 – 250 °C and complete toluene oxidation at 300 °C. However, for the complete oxidation of CO, the Ni/Co atomic ratio of 1/2 exhibits higher activity, converting 100% CO at 150 °C. The results show that NiO and CoOx are proved to be more active than the other for the oxidation of toluene and CO, respectively. The characteristic results show that high surface area, small particle size, good temperature reducibility, and oxygen species with high mobility in low-temperature regions are responsible for the catalytic performance of nickel cobalt spinel-type catalyst for toluene and carbon monoxide oxidation. The good stability of the Ni-Co oxide catalysts for the oxidation reactions originates from the strong Ni-Co interaction. [ABSTRACT FROM AUTHOR]

Carbon spheres are widely used in energy storage due to their adjustable particle size, controllable shape, and variable surface physical and chemical properties. However, there are still problems such as low specific surface area and unsatisfactory ion transport kinetics in K+ storage. Although increasing the specific surface area of the active material can increase the K+ storage sites, the contact area between the active material and the electrolyte also increases, aggravating the occurrence of side reactions and the consumption of the active materials. We developed an N-doped mesoporous hollow carbon sphere with a novel morphology-a smooth exterior and wrinkled interior structure with a carbon-supported pseudo-bilayer carbon structure (IW-MHCS). Its smooth outer structure sufficiently reduces the contact area with the electrolyte, and the wrinkled inner structure effectively increases the specific surface area. The obtained IW-MHCS exhibits superior rate performance (120.6 mAh g−1 at 5 A g−1) and sufficient capacity (202.7 mAh g−1 after 800 cycles at 1 A g−1) for K+ storage. This study provides a new insight into the structural design and morphological control of high-energy-storage carbon-based materials. [Display omitted] • A novel mesoporous hollow carbon spheres (HCSs) with pseudo-bilayer structure were synthesized. • The HCSs possess a smooth exterior surface and a wrinkled interior morphology. • The optimized sample exhibited excellent potassium storage performance. • The good electrochemical performance is ascribed to the unique microstructure of HCSs. [ABSTRACT FROM AUTHOR]

In recent decades, the concern over depletion of the world׳s petroleum reserves and environmental pollution has increased the demand to develop a renewable and environmental friendly fuel. Biodiesel, which mainly consists of Fatty Acid Methyl Esters (FAME) is one of the best substitutes for diesel fuel. Currently, vegetable oils, edible or non-edible, are the main resources of biodiesel. This review aims at providing comprehensive information and analyzes on biodiesel produced from edible and non-edible vegetable oils, their composition and specifications. Accordingly, the Fatty Acid (FA) profiles of 28 edible vegetable oils and 40 non-edible vegetable oils were collected. Their main specifications including sulfur content, density, viscosity, flash point, cloud point, pour point, cold filter plugging point, cetane number, iodine number, heating value, acid value and carbon residual before and after transesterification (vegetable oil and biodiesel, respectively) were analyzed in detail. Many researchers have developed prediction models to quantify biodiesel specifications to optimize its manufacturing and obtain biodiesel with the best specifications. Three factors that are especially influential are the fatty acids profiles, the degree of unsaturation within the FA structures and molecular weight. Accordingly, many models have been constructed on these features. There are also models that quantify the relationship between the biodiesel specifications and its thermodynamic properties or other specifications. Accordingly, the second part of this work was conducted on the existing prediction models. All the models were discussed along with their deviation in prediction. [ABSTRACT FROM AUTHOR]

The polymerization of the photocleavable monomer, o-nitrobenzyl methacrylate (NBMA), is investigated using photoinduced electron/energy transfer reversible addition-fragmentation chain transfer polymerization. The polymerizations under visible red ( λmax = 635 nm, 0.7 mW cm−2) and yellow ( λmax = 560 nm, 9.7 mW cm−2) light are performed and demonstrate rational evidence of a controlled/living radical polymerization process. Well-defined poly( o-nitrobenzyl methacrylate) (PNBMA) homopolymers with good control over the molecular weight and polymer dispersity are successfully synthesized by varying the irradiation time and/or targeted degree of polymerization. Chain extension of a poly(oligo(ethylene glycol) methyl ether methacrylate) macro-chain transfer agent with NBMA is carried out to fabricate photocleavable amphiphilic block copolymers (BCP). Finally, these self-assembled BCP rapidly dissemble under UV light suggesting the photoresponsive character of NBMA is not altered during the polymerization under yellow or red light. Such photoresponsive polymers can be potentially used for the remote-controlled delivery of therapeutic compounds. [ABSTRACT FROM AUTHOR]

Three-dimensional (3D) ordered mesoporous Ag/MnO2 catalyst was prepared by impregnation method based on 3D-MnO2 and used for catalytic oxidation of HCHO. Ag nanoparticles are uniformly distributed on the polycrystalline wall of 3D-MnO2. The addition of Ag does not change the 3D ordered mesoporous structure of the Ag/MnOx, but does reduce the pore size and surface area. Ag nanopartides provide suffident active site for the oxidation reaction of HCHO, and Ag (i l l) crystal facets in the Ag/MnO2 are active faces. The 8.9% Ag/MnO2 catalyst shows a higher normalized rate (10.1 nmol-s-1 m-2 at 110 °C) and TOF (0.007 s-1 at 110 °C) under 1300 ppm of HCHO and 150 000 h-1 of GHSV, and its apparent activation energy of the reaction is the lowest (39.1 kj/mol). More Ag active sites, higher low-temperature redudbility, more abundant surface lattice oxygen spedes, oxygen vacancies, and lattice defects generated from interaction Ag with MnO, are responsible for the excellent catalytic performance of HCHO oxidation on the 8.9% A g/MnO2 catalyst. The 8.9% A g/MnO2 catalyst remained highly active and stable under space velodty increasing from 60 000 to 150 000 h-1, under initial HCHO concentration increasing from 500 to 1300 ppm, and under the presence of humidity, respectively. [ABSTRACT FROM AUTHOR]

• High surface area catalyst prepared by a simple ammonia evaporation method. • La doping improves strong MSI and Ni dispersion. • La doping enhances CO 2 adsorption and decreases CO 2 adsorption energy. • Compelling low-temperature CO 2 methanation performance and stability. • Reaction intermediates include formate and CO* in low-temperature CO 2 methanation. The investigation into CO 2 conversion technologies has gained momentum due to escalating concerns about climate change and the pressing need for sustainable energy sources. While Ni-based catalysts have shown promise in CO 2 methanation, they often exhibit moderate activity. In this study, we sought to address this limitation by incorporating La into Ni nanoparticles supported on SiO 2 using the ammonia evaporation method. The La-doped Ni/SiO 2 catalyst demonstrated a significant improvement in CO 2 conversion, achieving a competitive 71.1 % compared to the 40.2 % observed with the Ni/SiO 2 catalyst at 275 °C. This improvement is evident in the high space–time yield of methane (STY CH4) at 227.3 mmol/(g·h) and a turnover frequency of (TOF CO2) at 0.36 s−1. The incorporation of La species modifies the electronic properties of Ni through electron transfer from Ni to La, resulting in a Ni-La interaction effect. Temperature-programmed reduction and desorption, probed by H 2 and CO 2 , reveal enhanced hydrogen atom spillover and stronger CO 2 adsorption capacity on the La-doped Ni-based catalyst. Density functional theory (DFT) calculations unraveled the underlying mechanisms of La-mediated enhancement, elucidating lower adsorption for CO 2 energy barrier and facilitated activation of C O bonds on the La-doped Ni-based catalyst. In-situ DRIFTS results indicated that, despite both catalysts following a CO pathway, La-doped Ni/SiO 2 possessed more accessible active sites for CO 2 methanation, whereas Ni/SiO 2 shows higher occupancy of active sites by adsorbed CO and formate species. [ABSTRACT FROM AUTHOR]

Liquid phase transmission electron microscopy (TEM) provides a useful means to study a wide range of dynamics in solution with near-atomic spatial resolution and sub-microsecond temporal resolution. However, it is still a challenge to control the chemical environment (such as the flow of liquid, flow rate, and the liquid composition) in a liquid cell, and evaluate its effect on the various dynamic phenomena. In this work, we have systematically demonstrated the flow performance of an in situ liquid TEM system, which is based on ‘on-chip flow’ driven by external pressure pumps. We studied the effects of different chemical environments in the liquid cell as well as the electrochemical potential on the deposition and dissolution behavior of Cu crystals. The results show that uniform Cu deposition can be obtained at a higher liquid flow rate (1.38 ÎĽ l minâˆ'1), while at a lower liquid flow rate (0.1 ÎĽ l minâˆ'1), the growth of Cu dendrites was observed. Dendrite formation could be further promoted by in situ addition of foreign ions, such as phosphates. The generality of this technique was confirmed by studying Zn electrodeposition. Our direct observations not only provide new insights into understanding the nucleation and growth but also give guidelines for the design and synthesis of desired nanostructures for specific applications. Finally, the capability of controlling the chemical environment adds another dimension to the existing liquid phase TEM technique, extending the possibilities to study a wide range of dynamic phenomena in liquid media. [ABSTRACT FROM AUTHOR]

Abstract: Cobalt chromium oxides with different Co/Cr ratios were prepared via co-precipitation method and their catalytic performances on methane combustion were evaluated from 300°C to 650°C at a space velocity of 36,000h−1. A significant improvement of activity was observed over the Co1Cr2 catalyst with a Co/Cr molar ratio of 1:2, and the methane conversion reached 90% at 464°C. The Co1Cr2 catalyst also showed excellent resistance to water vapor poisoning. In addition, the catalytic activity was inhibited in the presence of water vapor at the entire temperature range, while catalytic activity decreased only at low temperature in the presence of sulfur dioxide. Based on BET, TPR, XRD and XPS results, the superior performance of Co1Cr2 would origin from the higher valence and coordination number of the metal ions. Both Cr3+ and Cr6+ species were observed on the surface of cobalt chromites, and Cr6+ causes disorders in the spinel structure of cobalt chromites, which would enhance the adsorption of chemisorbed oxygen species and thus improve the catalytic performance, especially at low temperature. [Copyright &y& Elsevier]

Abstract: A serious of Fe/HBEA catalysts were prepared by impregnation methods under different calcination temperatures, and their catalytic activity in selective catalytic reduction (SCR) of NO x with ammonia were tested. The influence of calcination temperature on the microstructures of zeolite support, iron species, redox ability and reactant adsorption ability was investigated in detail by various characterization methods. Results showed that calcination temperature showed significantly influence on catalytic activity and selectivity of serial Fe/HBEA catalysts in NH3-SCR reaction. Some agglomeration of Fe/HBEA catalyst occurred at high calcination temperature (especially above 850°C), which result in drastic decrease of surface area and pore volume of Fe/HBEA catalysts. Meanwhile, the surface Lewis and Brönsted acidity of zeolite did not change when the calcination temperature was below 750°C, but significantly decreased above 850°C. Furthermore, high temperature aging led to some reduction migration of iron ions out of ion exchange sites on the Fe/HBEA catalyst. Consequently, iron oxide clusters are mainly formed upon Fe migration, which contributed to the SCR activity above 450°C. The deactivation of Fe/HBEA catalysts calcined at high temperatures was ascribed to surface area and pore volume decrease, Lewis and Brönsted acid sites inhibition, and the loss of iron ions and formation of iron oxide clusters. [Copyright &y& Elsevier]

[Display omitted] • Small and uniform CeO 2 nanoparticles were prepared on Al 2 O 3 (CA-T) using a two-step incipient wetness impregnation method. • Pt single sites anchored to step sites of small CeO 2 entities within CA-T were more stable than those anchored to crystal surface of large CeO 2 particles on regular ceria-alumina. • The reactivity of CO adsorbed on Pt sites decreased by Pt cluster step sites ≈ Pt cluster terrace sites > Pt cluster corner sites ≫ Pt single sites on CeO 2. • Abundant Pt cluster step and terrace sites as well as rich Pt-CeO 2 interfaces facilitated the activated Pt/CA-T catalyst for efficient CO oxidation at low temperatures. In heterogeneous catalysis, the promotion of low temperature activity and enhancement of thermal stability simultaneously especially for precious metal catalysts is always highly demanded but very challenging. Herein we report a novel Pt catalyst on ceria-alumina (CeO 2 /Al 2 O 3) support (Pt/CA-T) engineered by a two-step ceria deposition strategy, exhibiting superior thermal stability and low-temperature carbon monoxide (CO) oxidation activity after activation. Pt single sites anchored to engineered CeO 2 edge sites are much more stable than that to CeO 2 (111) surface, and such stable single sites can be transformed into highly active Pt clusters for efficient low-temperature CO oxidation. Active site identification indicates that the CO oxidation activity of different Pt sites follows such sequence: Pt cluster step sites ≈ Pt cluster terrace sites > Pt cluster corner sites ≫ Pt single sites on CeO 2. The excellent low temperature activity of activated Pt/CA-T catalyst for CO oxidation is associated with its abundant Pt cluster step and terrace sites as well as rich Pt-CeO 2 interfaces, which facilitate the adsorption of active CO species and superior oxygen activation/transfer ability. The present study provides new insights into the structure–activity relationship of Pt-CeO 2 -Al 2 O 3 catalyst, which can also guide the preparation of other highly robust supported catalysts for important industrial applications. [ABSTRACT FROM AUTHOR]

Polycyclic aromatic hydrocarbon (PAH) derivatives are mutagenic, carcinogenic, teratogenic and bioaccumulative pollutants. Investigations on hydroxylated PAHs (OH–PAHs) and Nitrated PAHs (NPAHs) in surface water are not enough. In this study, optimization and validation of an analytical method targeting nine kinds of OH–PAHs and one kind of nitrated PAH in environmental water samples are presented. The method was validated for linearity, limits of detection and quantification and recovery using spiked matrix. The linear range of most target compounds was 0.1–200 ng·mL−1 . However, the linear range of 1–hydroxy pyrene and 3–hydroxy benzo[a]pyrene started at 1 ng·mL−1 and the linear range of 1–hydroxy phenanthrene and 9–hydroxy benzo[a]pyrene could not reach 200 ng·mL−1 . All the correlation coefficients (r2 ) were over 0.997. The instrumental limits of detection (LOD) and method detection limits (MDL) ranged from 0.01 to 0.67 ng·mL−1 and 1.11 to 2.26 ng·L −1, respectively. With this method, a lake in Hebei province, China, were screened. Three kinds of target compounds were detected. The average concentration was around 2.5 ng·L −1, while the highest concentration reached 286.54 ng·L −1 . [ABSTRACT FROM AUTHOR]

While direct solar‐driven water splitting has been investigated as an important technology for low‐cost hydrogen production, the systems demonstrated so far either required expensive materials or presented low solar‐to‐hydrogen (STH) conversion efficiencies, both of which increase the levelized cost of hydrogen (LCOH). Here, a low‐cost material system is demonstrated, consisting of perovskite/Si tandem semiconductors and Ni‐based earth‐abundant catalysts for direct solar hydrogen generation. NiMo‐based hydrogen evolution reaction catalyst is reported, which has innovative "flower‐stem" morphology with enhanced reaction sites and presents very low reaction overpotential of 6 mV at 10 mA cm−2. A perovskite solar cell with an unprecedented high open circuit voltage (Voc) of 1.271 V is developed, which is enabled by an optimized perovskite composition and an improved surface passivation. When the NiMo hydrogen evolution catalyst is wire‐connected with an optimally designed NiFe‐based oxygen evolution catalyst and a high‐performance perovskite‐Si tandem cell, the resulting integrated water splitting cell achieves a record 20% STH efficiency. Detailed analysis of the integrated system reveals that STH efficiencies of 25% can be achieved with realistic improvements in the perovskite cell and an LCOH below ≈$3 kg−1 is feasible. [ABSTRACT FROM AUTHOR]

Critical catalysis studies often lack elucidation of the mechanistic role of defect equilibria in solid solubility and charge compensation. This approach is applied to interpret the physicochemical properties and catalytic performance of a free‐standing 2D–3D CeO2−x scaffold, which is comprised of holey 2D nanosheets, and its heterojunctions with MoO3−x and RuO2. The band gap alignment and structural defects are engineered using density functional theory (DFT) simulations and atomic characterization. Further, the heterojunctions are used in hydrogen evolution reaction (HER) and catalytic ozonation applications, and the impacts of the metal oxide heteroatoms are analyzed. A key outcome is that the principal regulator of the ozonation performance is not oxygen vacancies but the concentration of Ce3+ and Ce vacancies. Cation vacancy defects are measured to be as high as 8.1 at% for Ru‐CeO2−x. The homogeneous distribution of chemisorbed, Mo‐oxide, heterojunction nanoparticles on the CeO2−x holey nanosheets facilitates intervalence charge transfer, resulting in the dominant effect and resultant ≈50% decrease in overpotential for HER. The heterojunctions are tested for aqueous‐catalytic ozonation of salicylic acid, revealing excellent catalytic performance from Mo doping despite the adverse impact of Ce vacancies. The present study highlights the use of defect engineering to leverage experimental and DFT results for band alignment. [ABSTRACT FROM AUTHOR]

Schematic diagram of proposed next-generation artificial nitrogen cycle process based on electrochemical and photocatalytic reactions. [Display omitted] The nitrogen cycle is an important part of the global biogeochemical cycle, while the human activities have already caused a severe imbalance of the global nitrogen cycle. In this review, we proposed a new generation of artificial nitrogen cycle via electrochemical and photocatalytic reactions. In details, the N 2 from the air, NO 3 −/NO 2 − containing wastewater, nitrogen oxides from vehicle emission are all able to be utilized as a nitrogen source for the synthesis of NH 3 under ambient conditions. The oxidation of NH 3 , N 2 and nitrogen oxides can all achieve the aim of obtaining NO 3 −. Hydrazine can also be synthesized electrochemical and photochemical reactions. Utilizing electrochemical and photocatalytic processes enables to eliminate the hazardous of nitrogen-containing organic chemicals, and some inorganic nitrogen polluted wastewater. More importantly, coupling N-based reaction with other reaction like CO 2 reduction enables to synthesize some high-value chemicals such as urea. Then we highlighted some recent achievements in these reactions and proposed some future potential developing directions. The results and funding of this work may help us develop highly efficient catalysts and strategies for the artificial nitrogen cycle, repairing the broken nitrogen cycle balance. [ABSTRACT FROM AUTHOR]

Leveraging frustrated Lewis pairs (FLPs), we enabled efficient low-temperature CO 2 methanation using tailored Ni/CeO 2 catalysts. The distinct broom-like Ni/(0.06AB)CeO 2 catalyst composed of nanorods with abundant FLPs, created competitive low-temperature CO 2 methanation performance: 67.5% CO 2 conversion, 99.6% CH 4 selectivity and 0.27 s−1 CO 2 turnover frequency (TOF CO2) at 240 °C, along with robust stability at 300 °C for 100h. In-depth analyses via in-situ spectroscopy techniques and theoretical calculations unveiled synergetic CO and formate pathways in low-temperature CO 2 methanation over Ni/(0.06AB)CeO 2 catalyst. [Display omitted] • Tunable Ni/CeO 2 morphology by changing ammonium bicarbonate and cerium molar ratio. • The broom-like catalyst composed of nanorods is abundant in frustrated Lewis pairs. • Compelling low-temperature CO 2 methanation performance at 240 °C. • Dual interplay of CO and formate pathways in the low-temperature CO 2 methanation. • CO 2 methanation over Ni/CeO 2 proceeded by CO pathway with low energy barrier. The promising realm of carbon dioxide (CO 2) conversion offers a compelling avenue to advance environmental sustainability. This study introduces a novel approach by utilizing frustrated Lewis pairs (FLPs) for efficient low-temperature CO 2 methanation. Through a tailored ammonium bicarbonate (AB) precipitation method, we engineered Ni/CeO 2 catalysts abundant in FLPs. Various morphologies, including aggregated flakes, broom-like structures, and irregular granules, were achieved by modulating the AB-to-cerium molar ratio. The distinctive broom-like Ni/(0.06AB)CeO 2 catalyst, comprised of nanorods with abundant FLPs, exhibited outstanding low-temperature CO 2 methanation performance: 67.5 % CO 2 conversion, 99.6 % CH 4 selectivity, and 0.27 s−1 CO 2 turnover frequency (TOF CO2) at 240 °C, with excellent stability in a 100-h test at 300 °C. Furthermore, leveraging in-situ DRIFTS and in-situ Raman techniques, and DFT study, we unraveled CO 2 hydrogenation pathways and found a dual interplay of CO and formate pathways in the low-temperature methanation over Ni/(0.06AB)CeO 2 catalyst. [ABSTRACT FROM AUTHOR]

The diffusive gradients in thin films (DGT) technique serves as a passive sampling method, inducing analyte transport and concentration. Its application is widespread in assessing labile components of metals, organic matter, and nutrients across various environmental media such as water, sediments, and saturated soils. The DGT devices effectively reduce the porewater concentration through irreversible binding of solutes, consequently promoting the release of labile species from the soil/sediment solid phase. However, the precise quantification of simultaneous adsorption and desorption of labile species using DGT devices alone remains a challenge. To address this challenge, the DGT-Induced Fluxes in Soils and Sediments (DIFS) model was developed. This model simulates analyte kinetics in solid phases, solutions, and binding resins by incorporating factors such as soil properties, resupply parameters, and kinetic principles. While the DIFS model has been iteratively improved to increase its accuracy in portraying kinetic behavior in soil/sediment, researchers' incomplete comprehension of it still results in unrealistic fitting outcomes and an oversight of the profound implications posed by kinetic parameters during implementation. This review provides a comprehensive overview of the optimization and utilization of DIFS models, encompassing fundamental concepts behind DGT devices and DIFS models, the kinetic interpretation of DIFS parameters, and instances where the model has been applied to study soils and sediments. It also highlights preexisting limitations of the DIFS model and offers suggestions for more precise modeling in real-world environments. [Display omitted] • DGT technology reveals the kinetic processes of pollutants in soil or sediment. • DIFS model reflects the reservoir and resupply rate of labile analytes. • The limitations and correction approaches of the DIFS model should be considered. [ABSTRACT FROM AUTHOR]

Metal–organic frameworks (MOFs) are considered to be promising candidates for electrochemical water splitting. However, most MOFs are characterized by low electronic conductivity limiting their use as bulk materials for anodes and cathodes. Furthermore, the understanding of the critical parameters controlling the activity and stability of MOF electrocatalysts is still insufficient. Herein, a systematic analysis is presented of the key structural parameters controlling the oxygen evolution reaction (OER) performance and stability of a representative family of bimetallic NiFe‐MOFs, where the role of the metal cations on the accessible active sites and intrinsic activity can be investigated independently from the crystal structure. The models and in‐depth structural and morphological characterizations reveal a hierarchy of properties affecting the OER activity with accessible sites and intrinsic activity playing a major role in the charge transfer efficiency. Optimization of these properties and addition of a conductive support substrate leads to efficient MOF‐nanocomposite electrocatalysts achieving a low overpotential of 258 mV at a current density of 10 mA cm−2 with a small Tafel slope of 49 mV dec−1 and excellent stability for more than 32 h of continuous OER in alkaline medium. [ABSTRACT FROM AUTHOR]

In recent years, Nb-based oxides, especially Nb2O5, due to their unique structural advantages, have stimulated scholars' extensive research enthusiasm in the field of energy storage systems including lithium ion batteries (LIBs) and sodium ion batteries (SIBs), excellent chemical stability and outstanding rate capability dominated by pseudocapacitive nature. In addition, Nb-based oxides usually have a higher operating voltage (> 1.0 V vs Li+/Li), which can effectively prevent the decomposition of organic electrolytes and the formation of solid electrolyte interface films in batteries. This review systematically summarizes the different crystal structures of Nb2O5 and the lithium storage mechanism based on theoretical calculations, as well as the comparison of various synthesis strategies. In addition, the advanced research progress of niobium-based oxides as anode materials in LIBs and SIBs is summarized from the perspective of nanostructure control engineering that affects electrochemical performance. It also puts forward reasonable cognition and challenges for future research, which is conducive to the design of energy storage equipment that meets the needs of sustainable development. The design and optimization of various synthesis methods facilitate the formation of a variety of heterogeneous nanostructures, leading to reversible storage of Li and Na ions. [ABSTRACT FROM AUTHOR]

Tailoring the surface structure of Earth-abundant perovskite oxides can provide cost-effective, high-efficient, and durable electrocatalysts for oxygen evolution reaction (OER). However, the structural origin leading to high OER performance of perovskite is not fully understood. Here, we present a strategy of tuning the surface energy density of non-stoichiometric perovskite by creating surface defects in the 3D inverse opal LaCoO 3-x (3DIO-LaCoO 3-x) through a colloidal template strategy. The defective 3DIO-LaCoO 3-x , which has an enhanced surface energy density and a shift in the d-band centre of Co relative to the Fermi level, demonstrates significantly improved intrinsic OER activity, with a TOF (0.21 s−1) ten-folder larger than that of conventional LaCoO 3 nanoparticles (0.02 s−1). The defective surfaces of 3DIO-LaCoO 3-x are theoretically proven to alter the rate determining step of OER and significantly reduce the adsorption energies of the intermediate species, resulting in dramatically enhanced OER activity. Moreover, rich surface defects with high electrical conductivity can mitigate structural corrosion by fast transfer of charge through defective conductive channels, and thus enables long-term stability for the defective 3DIO-LaCoO 3-x. These results provide an effective approach for enhancing the intrinsic activity of perovskite for water oxidation towards understanding the surface structure engineering for perovskite-based materials. Image 1 • A surface defective 3D inverse opal LaCoO 3-x perovskite was synthesized. • Rich surface defects modified surface energy density and d-band centre of Co. • Intrinsic activity and stability against OER were significantly increased. • Defective sites reduced the energy barrier of the rate determining step of OER. [ABSTRACT FROM AUTHOR]

Herein, we demonstrate a method used to tune the selectivity of LaNiO3 (LNO) perovskite catalysts through the substitution of La with K cations. LNO perovskites were synthesised using a simple sol-gel method, which exhibited 100% selectivity towards the methanation of CO2 at all temperatures investigated. La cations were partially replaced by K cations to varying degrees via control of precursor metal concentration during synthesis. It was demonstrated that the reaction selectivity between CO2 methanation and the reverse water gas shift (rWGS) could be tuned depending on the initial amount of K substituted. Tuning the selectivity (i.e., ratio of CH4 and CO products) between these reactions has been shown to be beneficial for downstream hydrocarbon reforming, while valorizing waste CO2. Spectroscopic and temperature-controlled desorption characterizations show that K incorporation on the catalyst surface decrease the stability of C-based intermediates, promoting the desorption of CO formed via the rWGS prior to methanation. [ABSTRACT FROM AUTHOR]